The present invention relates in general to textile carding, and more particularly to an electromagnetically actuated torque-sensitive clutch for driving the feed roll of a carding machine.
The jamming of raw, non-carded, textile fibers between the feed roll and its associated feed plate is a well known problem encountered in the textile carding process, such jamming, for example, being caused by double laps of fibers or foreign objects drawn into the carding machine by the feed roll.
One means for minimizing such jamming is to provide a spring-supported feed roll for varying the feed space between the feed roll and its feed plate in accordance with the effective thickness of the raw textile fiber lap passing between the roll and the plate. U.S. Pat. Nos. 2,442,333 and 2,667,665 illustrate such feed rolls of the spring-supported type. While such a spring-supported feed roll may minimize feed roll jamming, the varying distance between the feed roll and its feed plate may permit entry into the carding machine of multiple laps or foreign objects of a size that could damage the carding machine or detract from the quality of the carded fibers.
Where it is desirable to minimize the degree of variance in the feed space between the feed roll and its feed plate to preclude entry of double laps or foreign objects into the carding machine, control means must be provided to respond to jammed feed roll conditions to prevent damage to the carding machine, while minimizing interruptions in the carding process. Such control means, for example, could automatically shut down portions of the card, such as the feed and doffer rolls, to allow manual unjamming of the feed roll while maintaining some of the carding process, such as card cylinder rotation, during such a jammed feed roll condition.
It is known that utilization of electromagnetically actuated clutches as part of the control means for driving feed and doffer rolls permits ready activation and deactivation of such rolls. U.S. Pat. No. 3,418,696 illustrates a carding machine including electromagnetic clutches in the drive trains of the feed and doffer rolls.